Air pollution, one of the environmental problems, has seriously harmed our life, as well as industrial and agricultural production. More attentions have been given to the treatment of air pollution. No matter in the industry or society, it is urgent to develop new air purification methods, and reduce the emission of harmful gas.
Currently, the air is mainly purified through ozone-catalytic and photocatalytic chemical decomposition, activated carbon adsorption and filtration. While generating a large amount of high concentration ozone to kill some viruses and bacteria, an ozone generator may kill the human leukocytes and cause canceration; the photocatalyst may take effect relying on the ultraviolet irradiation, and may harm human body and plastics; the activated carbon adsorption shall be replaced after reaching the saturated state one month later; the saturated one cannot kill any bacteria, and may cause bacterial reproduction.
The technology of inorganic membrane separation and purification is rapidly developed in recent years, and may be applied for filtering the bacteria, particulate matters and other pollutants in fluid and gas. Anodic aluminum oxide membrane is a kind of nano inorganic membrane for filtering with highly regular pores, and can realize the filtration through pores with the diameter of several to hundreds of nanometers, so it is an ideal air filtering material. However, the bacteria and pollutants rejected and held back during filtering may attach on the membrane surface or in the pores with a concentration higher than that in the water and air, making it more easy to reproduce bacteria; the bacterial reproduction on membrane surface or in pore will block the pore, increase the filtering resistance, and decrease the filtration flux significantly, which is one of major reasons for membrane pollution and blockage.
The nano-ZnO is excellent in antibacterial action and bacteriostasis; similar to the photocatalytic mechanism, the bactericidal mechanism is that the antibacterial action is realized through damaging the microorganism with reactive oxygen generated by nano ZnO. One layer of ZnO membrane which is adhered to the surface of sterile membrane will reduce the adhesion and reproduction of rejected bacteria on membrane surface, improving the service life of inorganic membrane, and reducing the pollution and blockage of membrane.